Abnormal periodic acid-Schiff (PAS)-positive substance in the islets of Langerhans, pituitaries and adrenal glands of 139H scrapie-infected hamsters

Previous studies showed that the 139H strain of scrapie injected intra-cere brally in hamsters caused obesity, and extensive histopathological changes in islets of Langerhans and pituitaries. In the current study, we report th at an abnormal granular substance, which stained positively with periodic a cid-Schiff (PAS-positive substance; PPS), was found in the islets of Langer hans, pituitaries, adrenal glands, in the lumens of blood vessel cores (BVC s) and in blood vessels in 139H-infected hamsters, but not in either 263K-i nfected or control hamsters. This substance was found in the endocrine orga ns, forming grape-like or plaque-like structures, which were small, round t o ovoid, and homogenous measuring up to 7 mu m in diameter and usually grou ped in clusters. PPS was not found in the brains of control or scrapie-infe cted hamsters. Using immunostaining for amyloid protein (PrP, beta A4), as well as Congo red and thioflavin-S stains, no evidence was found of amyloid plaque formation in the islets of Langerhans, the adrenal glands, or the p ituitaries of 139H- or 263K-infected hamsters. PPS might relate to the path ological changes in the endocrine organs in 139H-infected hamsters.